The present invention relates to a voice warning device, and more particularly relates to a voice warning device adapted to be fitted to a driver's compartment which is also provided with an entertainment sound production system which comprises a plurality of speakers.
In most modern automobiles or other means of transportation it is customary for an entertainment sound system to be fitted within the compartment in which the driver or pilot is seated, in order to entertain the driver or pilot and the passengers, and thereby to improve the comfort and the drivability of the automobile or the like by relieving the mental fatigue of the occupants. Such an entertainment sound system produces its output sound through one or a plurality of speakers. Further, in the case of a high quality entertainment sound production system, invariably it utilizes at least two speakers, in order to provide a stereo effect and a good distribution of sound within the air volume of the driver and passenger compartment.
Further, in almost all automobiles or other high quality transportation means there are provided various warning devices for indicating to the driver or pilot and/or the occupants of the facility the presence of various problem conditions in the operating conditions of the facility. For instance, such warning devices may indicate to the driver of the automobile that engine oil pressure is low, that one or more doors of the automobile are not properly closed, that fuel level of the fuel tank of the automobile is low, that an oil filter of the automobile requires to be changed, or the like. Such a warning device may either convey a signal to the driver by means of a warning light or a warning sound.
In the past, such warning sounds which have been used to indicate problem conditions to the driver have been simple mechanical sounds, such as those produced by buzzers or bells. Such warning sounds are easily discernible to the driver, even if he is operating the entertainment sound production system at a fairly high level, because the warning sounds are quite unlike the typical sounds emitted by such an entertainment system.
However, recently there have been developed various so-called voice warning devices, which produce voice warnings to the driver in a simulated or synthesized human voice, specifically indicating various problem conditions. In other words, such a voice warning device emits a sequence of words precisely specifying the condition to be warned about. Difficulties and problems have arisen with such voice warning devices for several reasons. Such prior art voice warning devices have utilized their own special independent speakers. However, it has been found that the interrupting capability of such a voice warning device, when the driver is listening to sounds produced by an entertainment sound production system, has been much lower than that of the sounds emitted by buzzers or bells. The reason for this is considered to be that, when the driver's listening attention is being directed to entertainment sound sources which despatch a series of sounds which produce a continually changing mental reaction in the brain of the driver, the verbal sound from the voice warning device, which itself is not of a warning nature, and yet which must be attended to from the very beginning for its meaning to be correctly understood, cannot immediately divert the driver's listening attention from the entertainment sound sources to the warning voice signal source, with the entertainment sound sources continuing to despatch the entertainment sounds. Further, when the voice warning device has its own independent speakers, the cost has been rather high, and also space has been required for fitting such independent speakers.